Project Summary?Abstract While total shoulder arthroplasty (TSA) is the preferred surgical treatment for advanced glenohumeral arthritis, a subset of patients does not experience improvement or sustains a complication. Mean TSA complication rates have ranged from 10-17%, with glenoid component loosening reported as the most common long-term complication of anatomic TSA and a common reason for revision surgery. While complications can lead to poor clinical outcomes, multiple studies have also shown associations between baseline demographic, disease- related and surgical factors, and clinical outcomes. Despite these prior studies, the factors associated with poor short- and long-term clinical outcome after anatomic TSA are still not well understood, in part due to the lack of large prospective cohort studies allowing for multivariable analysis. Our proposal?s objective is to identify the factors associated with short- and longer-term clinical and radiographic outcomes following anatomic TSA. Our approach will utilize two unique, prospective TSA cohorts ongoing at our institution to allow for simultaneous investigation of short and longer-term clinical outcomes, as well as the relationship between the two through the assessment of radiographic factors not possible with routine imaging: a larger cohort (over 1,200 projected cases) collecting baseline demographic, disease-related and surgical factors, together with 1 year clinical outcomes (Patient Cohort 1); and a smaller cohort (n=152) collecting CT imaging-based measures, as well as minimum 5 year clinical outcomes (Patient Cohort 2). Specific Aim 1 will use Patent Cohort 1 to identify the risk factors associated with short-term clinical outcomes at 1 year after primary anatomic TSA. Specific Aim 2 will use Patient Cohort 2 to conduct exploratory analyses of the incremental contribution of CT imaging-based radiologic factors to the prediction of longer-term clinical outcomes at minimum 5 years after primary anatomic TSA, beyond that provided by the perioperative risk factors identified in Specific Aim 1. We expect to show that baseline mental health status, pre-operative opioid use, pre-operative Penn Shoulder Score (PSS) or Single Assessment Numeric Evaluation (SANE) score, Walch classification, subscapularis management, and implant position will independently associate with 1-year patient-reported outcomes (PSS, SANE) after controlling for other demographic, disease-related, and surgical factors (Aim 1). We also anticipate that after adjusting for the risk factors investigated in Aim 1, glenoid component shift (translation and/or rotation) and central peg osteolysis at minimum 2 and/or 5 years post-operatively will associate with worse patient-reported outcomes (PSS, SANE) at minimum 5 years, and that the pre-operative Walch classification and joint line medialization and the presence of central peg osteolysis at minimum 2 years will associate with composite glenoid component shift at minimum 5 years (Aim 2). Identifying significant risk factors that are important to clinical outcomes following anatomic TSA would allow for the design of future prospective clinical trial(s) to investigate modification of these factors either directly or indirectly through pre-operative intervention or modification of surgical treatment and/or patient selection based on these factors, with the aim to improve outcomes and survivorship following anatomic TSA.